On 17 August 2025 at 08:26 Adrian R2 Said:

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I wonder if 3 phase power, like roof solar, will become a desirable thing for future house buyers? If so you could mentally reclassify/justify some of the cost as an “investment”.

No problem with the technology, Adrian is right:  it’s all about the investment!  Money – installation cost, maintenance cost, and return on investment.

Very few domestic customers have any need for 3-phase, in fact 3-phase is a pain in the bum in an ordinary home.     One reason is safety: getting between 240V live and neutral is shocking: accidentally connecting self across two phases (440V) risks serious burns and electrocution.   If installed, 3-phase is contained in a kitchen, heating system, workshop, EV charger, or maybe a solar-panel.

From the supplier’s perspective, a home workshop doesn’t consume enough £power to offset the cost of the installation.  My workshop uses less power than my washing machine and dish-washer.

How much a 3-phase installation costs varies wildly, so some sort of survey is needed.  My previous home got single-phase from a substation, other side of the road, about 200 yards away.  Providing 3-phase to my planned workshop meant a long trench across and along the road, and then either passing the cable through the house, or routing it round a back-lane.  The back-lane route was about 400 yards total. No poles in the street, so I guess they would have insisted on an expensive trench.   For a single home, the cost of the work is eye-watering: much cheaper if all the homes in the street are upgraded at the same time.

Conversely, my present home has easy access to the 3-phase system: bare wires strung overhead about 10m away.   I’ve not bothered because only my lathe needs 3-phase, and it came with a VFD.   Would be worth it if I owned two or more big 3-phase machines of the type that don’t adapt to a VFD.

New single-phase installations can also be expensive.  I know of a couple doing a barn conversion who were quoted £12,000 for single-phase, a nasty last-moment surprise.  Reason: the barn is distant from the network, and supplying it means digging a long trench through a nearby village, then putting up several poles, and a pole-pig.   The customer bears all the costs, unlike a housing estate where the bill is shared between many.  Not sure what’s happened since: they had already borrowed all they could afford.

EV rechargers are set make domestic 3-phase commonplace, in which case costs will drop.   At present, domestic 3-phase is expensively tacked on to a system designed to deliver single-phase as cheaply as possible.  For historic reasons!  If enough domestic customers need it, entirely possible to make 3-phase much more accessible.  Yes it will cost time and money, but we are not stuck with existing infrastructure.

Dave

On 17 August 2025 at 11:50 John Haine Said:

<p style=”text-align: left;”>I believe that 3ph is standard for German homes.</p>

3 phase in domestic installations in France used to be common for water heating and heating the house in big country houses, based on cheap power from the growing nuclear power network, oil is expensive, town gas not available outside town and cities so it made sense.

I’ve got 3 phase in our big barn as it used to be a sawmill prior to 2000, after that the brits we bought the property from used it for ancient wood working machinery, so the 400 volt supply existed when we arrived. I just tap 230 volts single phase @ 9 kw puissance  from the enormous old 400 volt tableau and meter, enough for lights, workshop, beer fridge and freezers.